Applicator having a ribbed, bristle-forming filament all around

ABSTRACT

The invention relates to an eyebrow applicator ( 1 ) comprising bristle-forming filaments ( 5 ) retained in a clamped manner between at least two wires ( 3, 4 ) twisted together, characterised in that at least one portion of the bristle-forming filaments ( 5 ) has a cross-section (perpendicular to the longitudinal axis thereof) formed by a solid core ( 7 ) from which at least 8, preferably at least 10 ribs ( 8 ) and ideally 12 ribs ( 8 ) protrude radially on all sides, wherein the outer diameter of these filaments ( 5 ) is at least 0.25 mm, the length of the bristles ( 6 ) formed by these filaments ( 5 ) is max, 3 mm, and the material of these filaments ( 5 ) has a hardness of &lt;60 Shore D.

TECHNICAL BACKGROUND

For a long time there has been a widespread need for applicators for applying mascara mass, cosmetic mass to the eyebrows or cosmetic mass to the main hair, which have the largest possible mass storage capacity, i.e which are loaded with the cosmetic to be applied as far as possible already after being immersed in and pulled out of the supply once so that the entire application process can be carried out without immersing the applicator again.

In order to remedy this, it has been proposed in a wide variety of variants to incorporate more or less narrow grooves into the finished bristle facing of a wire core applicator, i.e. areas in which there are lower-lying short bristles that are surrounded by higher bristles. The basic idea here is that cosmetic can be retained in the grooves formed in this way, which is not being completely stripped off by the wiper when the applicator is pulled out. This actually improves the storage capacity significantly.

However, due to the relatively large-scale and noticeable grooves, the haptic behavior of the applicator is impaired for the perception of many female users.

Then, some very different variants of applicators with sprayed bristles have already been proposed, which are designed so that they have an improved mass storage capacity. Sprayed bristles however still offer only a weaker performance in terms of bend recovery capabilities and are therefore as well not the single solution.

THE OBJECTIVE OF THE INVENTION

The invention is based on the objective to create an applicator which is characterized by a particularly good mass storage capacity on the one hand, and which also enables an exceptionally smooth application experience on the other.

THE SOLUTION ACCORDING TO THE INVENTION

To solve this problem, it is proposed to build an applicator which consists of bristle-forming filaments clamped between at least two wires that are twisted together. A filament usually forms two bristles. The part of a filament that extends from the clamping point between the twisted wires to the radially outer free end is named bristle. According to the invention, a TPE is used for the bristle-forming filaments. The elastomers from the TPE group are characterized by their particular flexibility. It is to be ensured that even within the TPE a particularly soft material is used, namely a material that has a hardness of less than 60 Shore D and ideally 55 Shore D, ideally with max. 1% tolerance. The smallest possible Shore hardness within the scope of the invention is 40 Shore D and in exceptional cases 35 Shore D.

In principle, such a material would only be suitable for the production of bristle-forming filaments to a very limited extent, since it is actually too soft to produce bristle-forming filaments which subsequently lead to bristles with sufficient bending resistance. In order to compensate for this, not only is the outer diameter of the filaments increased, but also additional ribs are provided which protrude radially outward on all sides from the solid core cross-section of the bristle-forming filament. Grooves, which are characterized by a particularly high mass storage capacity, are formed between the ribs.

The ribs in conjunction with the enlarged diameter and the, on the other hand, quite soft material result in a bristle that is not only very supple, but also does not buckle prematurely.

Surprisingly, compliance with these specifications also results in an unexpectedly useful storage effect. This is because the grooves between the ribs can not only absorb material particularly well, but also collapse easily locally when the later bristles come into contact with the treated surface or come into contact with the hair to be treated and bend in the process due to the extremely soft plastic that is used for the bristle-forming filaments. As a result of this collapse, the stored material is released very well. As a result, this type of filament leads to bristles that show an exceptionally good capacity for mass storage and re-release with a special, haptic experience on skin contact that has never been seen before.

The bristles according to the invention must, as far as the specific dimensioning is concerned, be matched very precisely to the individual case, since the choice of material according to the invention and the geometric configuration goes into a range that is not variable at will anymore concerning the closely related length and thickness parameters.

Where these bristles are used to build an eyebrow applicator, the outside diameter of the filaments should be at least 0.25 mm in an undisturbed area. Smaller diameters lead to a disruption of the desired storage function of the grooves. The length of the bristles formed by these filaments should be a maximum of 3 mm for an eyebrow appliator, measured from the pinching wire core to the radially outward free end. Ideally, the bristles are at least 1.5 mm long.

Where these bristles are used to build a mascara applicator, the outside diameter of the filaments should be at least 0.35 mm in an undisturbed area. Smaller diameters lead to a disruption of the storage function of the grooves which is desired for the application of the typically very highly viscous mascara mass. The length of the bristles formed by these filaments should be a maximum of 6 mm in the case of an eyebrow applicator, measured from the pinching wire core to the radially outward free end. Ideally, the bristles are at least 2 mm long.

Where these bristles are used to build a main hair applicator, the outside diameter of the filaments should be at least 0.7 mm at an undisturbed point. In many cases it is not favorable if the outer diameter of the filaments is more than 0.9 mm. Smaller diameters are unsuitable for treating the main hair, which usually offers some resistance, since they make the bristles too sensitive to kinking. The length of the bristles formed by these filaments should be a maximum of 12 mm in the case of an eyebrow applicator, measured from the pinching wire core up to the radially outward free end.

Ideally, the bristles are at least 5 mm long.

PARTICULARLY PREFERRED DESIGN POSSIBILITIES

A particularly advantageous further development option is to produce the filaments according to the invention from a thermoplastic elastomer (TPE). Despite its according to the invention low Shore hardness D, this material allows fine structures to be extruded, such as the filaments required here. Surprisingly, even with the very high degree of softness chosen here, a TPE is clearly superior in terms of the bend recovery capacity, while at the same time ensuring the required relative movement behavior of the ribs relative to the solid core, when the later bristle is having contact with the surface or hair to be treated and is bent in the process.

Further advantageous design options emerge from the subclaims.

The following description of various preferred embodiments based on the figures also gives rise to further design options, modes of operation and advantages.

FIGURE LIST

FIG. 1 shows an applicator according to the invention in the form of a mascara brush in a general overview.

FIG. 2 shows a cross section (perpendicular to the longitudinal axis of the filament) of a filament as it is used for bristle formation on an applicator according to FIG. 1.

FIG. 3 shows the same as FIG. 3, however related to with more detail.

FIG. 4 shows an enlarged detail from FIG. 3, cut out in the 11 o'clock position.

FIG. 5 shows a filament according to the invention with a straight end and a cross section (perpendicular to the filament longitudinal axis FL), as shown by FIGS. 2 and 3.

FIG. 6 shows a filament according to the invention with a pent-roof-like end and a cross section (perpendicular to the filament longitudinal axis FL), as shown by FIGS. 2 and 3.

FIG. 7 shows a filament according to the invention with a gable roof-like end and a cross section (perpendicular to the filament longitudinal axis FL) as shown by FIGS. 2 and 3.

FIG. 8 shows a filament according to the invention with a pyramidal end and a cross section (perpendicular to the filament longitudinal axis FL), as shown by FIGS. 2 and 3.

FIG. 9 shows a detail from a cross section of a filament with shallow grooves.

FIG. 10 shows a detail from a cross section of a filament with medium-deep grooves.

FIG. 11 shows a detail from a cross section of a filament with deep grooves.

EMBODIMENTS OF THE INVENTION Mascara Applicator

A first overview of an applicator according to the invention 1 in the form of a mascara applicator is shown in FIG. 1. This mascara applicator consists of a core 2, which in turn has been made from at least two wires twisted spirally with one another. The core 2 defines a longitudinal axis L of the applicator. Before the twisting, a number of bristle-forming filaments 5 (see FIG. 5) have been inserted between the two wires 3 and 4. These are then held clamped between the two wires 3 and 4 by twisting them. Each filament 5 forms two bristles 6 which protrude from the core 2 in different directions. The trim of the mascara applicator, which cannot be identified qualitatively in greater detail with reference to FIG. 1, consists (predominantly, essentially or completely) of bristles in the form of the filaments according to the invention.

Said specially designed bristle-forming filaments have a filament longitudinal axis FL. They are shown as such—in various variants—in the context of FIGS. 5, 6, 7 and 8. However, the respective image of the filament is strongly “compressed” in the direction of its longitudinal filament axis FL.

The cross section according to the invention of a bristle-forming filament 5 to be used according to the invention is shown in FIG. 2.

It can be seen immediately that this bristle-forming filament used according to the invention has a solid core in the cross section running perpendicular to its longitudinal axis, which is denoted by the reference number 7 and which is marked in FIG. 3 by the broken line.

At least eight and in the present case ten ribs 8 protrude outward in the radial direction from this bristle-forming core. The ribs protrude outward on all sides relative to the filament longitudinal axis FL, which usually forms the center. This means at each point of the outer jacket of the core, there is preferably a rib 8 present, which protrudes outward in the radial direction, as shown in FIG. 3. The adjacent ribs 8 meet where the cross-section merges into said solid core 7.

As can best be seen from FIG. 3, it is preferably such that each of the ribs 8 is configured to be continuous in the direction of the longitudinal axis FL of the respective bristle-forming filament 5, that is to say has no or essentially no interruption.

It is noteworthy that the maximum diameter DKmax of the solid core 7 is preferably more than twice the radial extension Re of a rib. This can be seen clearly from FIG. 3. The maximum outside diameter of the filament, which it preferably has at any height along its longitudinal filament axis FL, bears the reference symbol DAmax, cf. FIG. 3.

To put it even more succinctly, one can say that the following relationships should ideally be observed for the maximum outer diameter DAmax and the maximum core diameter of the solid core

DKmax:

-   Eyebrows: DAmax smaller 0,36/DKmax smaller 0,26 -   Mascara: DAmax bigger 0,30/DKmax bigger 0,20 -   Main-/Headhair: DAmax smaller 0,90 and bigger 0,50/DKmax smaller     0,70

The bristle-forming filament according to the invention preferably consists of a thermoplastic elastomer, that is to say of an elastomer from the TPE family. Thermoplastic elastomers are characterized by the fact that they are particularly soft and pliable. This gives the bristles 6, which are formed by the bristle-forming filaments 5 clamped between the wires 3, 4, a particularly good conformability. Nevertheless, in order not to let the bristles become too soft and pliable, the invention provides that a comparatively large bristle outer diameter is realized, as already stated numerically above for a mascara applicator and also defined later for eyebrow applicators and brushes for main hair.

In the light of this consideration, the function of the radially outwardly protruding ribs 8 is revealed. They increase the effective outer diameter DAmax of the bristle-forming filament and thus the flexural strength of the later bristle 6, even if extremely soft material is used.

However, associated with this, there is also another very positive aspect. This goes back to the fact that a relatively deep groove 9 is formed between two ribs 8 that are directly adjacent in the circumferential direction. Ideally with all applicators—at least with mascara and/or main hair applicators—the radial depth RT of such a groove 9 between two ribs 8 adjacent in the circumferential direction is greater than 0.08 mm. For eyebrow applicators, this value is optionally reduced from the aforementioned value to 0.05 mm.

As a result, a not inconsiderable amount of the cosmetic product to be applied can be placed in these grooves 9, which is not stripped off by the scraper when the applicator is pulled out of the supply comprising the substance to be applied (according to this embodiment example mascara mass).

Instead, the substance stored in these grooves 9 is only released—usually gradually—when the bristle formed by the filament in question bends back and forth several times in contact with the surface to be treated or the hair to be treated and thereby the substance in the area of the grooves 9 is pushed out. This ideally gradual release of the substance to be applied allows the applicator to work very long-term without having to “reload” in between.

The storage effect according to the invention is further enhanced by the fact that the ribs 8, considering the circumferential direction, have a width that changes in the radial direction.

As can best be seen from FIG. 4, the ribs here each have a base section 10 and a tip section 11. The base section 10 is here that section of a rib which, viewed in the radial direction, lies closer to the center of the cross section formed by the filament longitudinal axis FL. Correspondingly, the tip section 11 of a rib is that section of a rib which, viewed in the radial direction, lies further away from said center.

It is noteworthy that the tip section 11 of the ribs 8 according to the invention—as soon as one moves in the radial direction outward from the transition base section/tip section in the circumferential direction—by far predominantly (more than 50%, better than 75%) has a greater extent EU1, as the transition between the base section and the tip section of the relevant rib, the extent of which in the circumferential direction is only EU2, cf. FIG. 4.

As a result, two ribs 8 directly adjacent to each other in the circumferential direction form a groove 9 between them, the width of which gradually decreases again in the radial direction from the inside to the outside. This reinforces the holding effect that the relevant groove 9 gives the substance to be applied.

It has proven to be particularly favorable for the holding effect if the transition between the base section 10 and the tip section 11 of a rib 8 forms a kink, meaning a geometry in which max. an imaginary measuring circle 12 can nestle with a maximum diameter of 0.015 mm, cf. FIG. 4.

At this point it should be said that it has also proven to be very beneficial for the all-round wetting of a hair that has penetrated the groove between two ribs if the groove base narrows in a V-shape—ideally into a narrowest area, the one at the base kink forms, i.e. shows a geometry in which at most an imaginary measuring circle 12 with a maximum diameter of 0.015 mm can nestle, cf. FIG. 3.

It has proven to be particularly favorable to make the tip section of a rib predominantly circular in cross section (or alternatively, to approximate it in a multipolygonal manner). This preferably means that the cross-sectional profile, seen perpendicular to the filament longitudinal axis FL, has a circular profile over an angle beta of more than 220°, cf. FIG. 3.

It can be clearly seen from FIGS. 3, 5, 6, 7 and 8 that each groove 9 between two ribs 8 directly adjacent in the circumferential direction preferably runs completely straight in the direction along the filament longitudinal axis FL.

In exceptional cases, however, it can nevertheless be useful to leave the dogma of the straight rib 8 and to make the ribs 8 spiral, i.e. in such a way that they wind around the filament longitudinal axis FL like a helical line.

As a result, however, there is usually a somewhat lower release of material from the bristle 6 formed by the filament 5 in question when it comes into contact with the surface to be treated or the hair to be treated.

One can only guess from FIG. 1 that the applicators according to the invention are preferably characterized in that the number of filaments clamped per turn of their wire core is relatively small. It is predominantly or for all turns between 3 and 15 filaments per turn.

This results in a very special application behavior because, viewed overall, there are fewer bristles available on the finished applicator that can store the mass to be applied. However, this is overcompensated by the extremely increased storage capacity of the individual bristles, which they receive from their surface structured according to the invention.

It should also be noted that the filaments according to the invention which are used here for forming bristles are preferably continuously extruded filaments. This is very advantageous in so far as the filaments are strongly stretched in the direction of their longitudinal filament axis as they pass through the extruder nozzle. This means that extrusion is not just a manufacturing process, but also a physically reflected “product-by-process” feature, because extrusion means that the molecular chains of the filament-forming plastics are aligned to a high degree in the same direction and increasingly parallel to the filament longitudinal axis, i.e. drawn out. As a result, such filaments or the bristles formed from them have an excellent ability to straighten up, which is also referred to as bend recovery ability. In this respect, they are physically different (namely with regard to their sub-macroscopic structure) and therefore clearly superior to sprayed bristles.

It is particularly favorable if the filaments used according to the invention for forming the bristles consist of pure TPE. Particularly preferred TPE used are the subgroups TPE-A and TPE-S, which on the one hand can be extruded particularly well with the required dimensional accuracy and on the other hand have a superior bend recovery capacity, which is an essential property for a material, used for the production of bristle-forming filaments.

Especially for applications where however long-term stability is not required because the applicator is more of a disposable applicator, it can also be useful to add filler materials to the TPE that forms the said filaments. A filler material which has just proven to be very suitable for use in accordance with the invention is calcium carbonate. Added in small amounts, calcium carbonate hardly changes the application properties of the TPE. Used in slightly larger quantities, the elasticity is reduced. This is process-wise easily controllable, i.e. the desired bristle properties can be set very quickly and efficiently using the teaching according to the invention.

Charcoal has proven to be just as suitable.

Regardless of whether with or without filler material, the material of the bristle-forming filaments is always chosen according to the invention n such a manner that it has a hardness that is below 60 Shore D and ideally 55 Shore D, plus any tolerance values, as already mentioned above.

Investigations carried out in connection with the invention have shown that the bristles according to the invention, which are provided with a very large diameter, have difficulties in developing the desired separation effect due to their design according to the invention.

In order to remedy this problem it has been found beneficial to sharpen the bristles. Sharpening is typically only carried out after the filaments have been installed and the wires holding them twisted, i.e. at a stage in which each filament has already formed two bristles.

For this purpose, the bristles are usually fed to a grinding wheel. In the simplest case, all or a predominant part of the bristles are given a simple, one-dimensional bevel, which gives them a pent-roof-like bevel 13 at their free end, which FIG. 6 illustrates in more detail.

An even better separation effect can be achieved if the bristles or at least the majority of the bristles are ground from two sides so that they have a chisel-shaped tip or a bevel 14 in the shape of a gable roof. This constellation is visualized in FIG. 7. Where the two ground surfaces meet at the free end, a ridge-like point line 15 is formed which can easily penetrate between two hairs, even when the bristle is actually quite soft and therefore kinks easily.

An even more favorable constellation is shown in FIG. 8. Here, the free end of each or at least the majority of the bristles has been ground from four sides. As a result, the bristle in question comprises a pyramidal bevel 16. It is evident that the tip 17 of the pyramid can penetrate particularly well into a field with tangled hair and can develop a separating effect here.

SECOND EMBODIMENT

The second embodiment is an eyebrow applicator. All of the above applies identically to it. The figures also apply. The only difference is that the parameters of the filament as well as bristle outer diameter and the bristle length that are required for eyebrow application that were already specified at the beginning must be observed.

THIRD EMBODIMENT

The third embodiment is a main hair applicator. All of the above applies identically to him, and the figures also apply. The only difference is that the parameters of the filament required for the main hair application as well as the outer bristle diameter and the bristle length that were already specified at the beginning must be observed.

General Comprehensive Considerations

The tip section 11 of each or the predominant number of the ribs 8 is preferably designed to be circular in cross-section, as can also be seen from the figures explained below.

It is particularly favorable—depending on the particular application of the applicator—to maintain certain depths for the grooves 9.

If the applicator which is equipped with the fiber according to the invention is an eyebrow applicator, i.e. an applicator that is intended for the application of a cosmetic to the eyebrows or is even specialized in this, then the depth of the groove 9 should be dimensioned so that the maximum depth of groove 9 is chosen in such a way that the circle with diameter DKmax, which forms the sheath of the solid core 2 and the circles inscribed in the tip sections 11 with the radius r are still tangent, cf. FIG. 9, which shows a relatively shallow depth for this application, in which the said circles intersect, and FIG. 10, which shows the maximum depth for this application, since the said circles are only tangent. It should be noted that in FIGS. 9 to 11 the radius which is provided with the reference symbol DKmax is the radius which belongs to the maximum diameter of the core 2.

If the applicator which is equipped with the fiber according to the invention is a mascara applicator, i.e. an applicator that is intended for the application of a cosmetic on the eyelashes or is even specialized in this, then the depth of the groove 9 should be such that the groove 9 is at least deep enough that the circle that forms the sheath of the massive core 2 and the circles inscribed in the tip sections 11 are still tangent or the depth of the groove should be made larger so that the said circles no longer tangle (and certainly do not intersect), cf. FIG. 11.

If the applicator to which the fiber according to the invention is to be applied is an applicator for the main hair, i.e. an applicator which is intended for the application of a cosmetic on the main hair or is even specialized in this, then the depth of the groove 9 should be such that the groove 9 is always made so deep that the circle that forms the sheath of the solid core 2 and the circles inscribed in the tip sections 11 no longer tangle (and certainly do not intersect), cf. again FIG. 11.

REFERENCE LIST

-   1 applicator -   2 core -   3 wire -   4 wire -   5 bristle-forming filament -   6 bristle -   7 massive core of a filament -   8 radially outwardly protruding rib -   9 groove -   10 base section of a rib -   11 tip section of a rib -   12 measuring circle transition base section/tip section -   13 pent roof-like bevel -   14 gable roof-like bevel -   15 ridge-like tip line -   16 pyramidal bevel -   17 tip -   L longitudinal applicator axis -   FL longitudinal filament axis -   DKmax maximum diameter of the massive core -   DAmax maximum outside diameter of the filament -   Re radial extension of a rib -   RT radial depth of a groove -   ALPA fillet angle -   Beta angle -   EU1 extension at the transition area -   EU2 extension of the base section 

1. A cosmetic applicator with bristle-forming filaments held clamped between at least two wires that are twisted together, wherein at least some of the bristle-forming filaments have a cross section, perpendicular to a longitudinal axis of a respective filament, which consists of a solid core from which at least 8 ribs protrude radially on all sides, with an outer diameter of these filaments being at least 0.25 mm, a length of the bristles formed by these filaments having a maximum of 3 mm, and a material of these filaments having a hardness of <60 Shore D.
 2. A mascara applicator with bristle-forming filaments held clamped between at least two wires that are twisted together, wherein at least some of the bristle-forming filaments have a cross section, perpendicular to a longitudinal axis of a respective filament, which consists of a solid core from which at least 8 ribs protrude radially on all sides, with the outer diameter of these filaments being at least 0.35 mm, a length of the bristles formed by these filaments having a maximum of 6 mm, and a material of these filaments having a hardness of <60 Shore D.
 3. A main hair applicator with bristle-forming filaments held clamped between at least two wires that are twisted together, wherein at least some of the bristle-forming filaments have a cross section, perpendicular to a longitudinal axis of a respective filament, which consists of a solid core from which at least 8 ribs protrude radially on all sides, with an outer diameter of these filaments, at an undisturbed point, being at least 0.7 mm, a length of the bristles formed by these filaments having a maximum of 12 mm, and a material of these filaments having a hardness of <60 Shore D (tolerance 5%).
 4. The applicator according to claim 1, wherein said filaments comprise a thermoplastic elastomer (TPE).
 5. The applicator according to claim 4, wherein the TPE is either mixed with a filler material calcium carbonate or charcoal or is used unfilled.
 6. The applicator according to claim 1, wherein the material of said filaments has a hardness of at least 55 Shore D.
 7. The applicator according to claim 1, wherein a maximum diameter of the solid core is more than 2 times a radial extent of at least one of the ribs.
 8. The applicator according to claim 1, wherein a radial depth of a groove between two adjacent ribs in a circumferential direction is bigger than 0.06 mm.
 9. The applicator according to claim 1, wherein a groove between two circumferentially adjacent ribs has a V-shaped cross section—in a region of a base of the groove.
 10. The applicator according to claim 1, wherein a number of filaments clamped per turn is between 3 and 15 for all turns.
 11. The applicator according to claim 1, wherein the at least two twisted wires are twisted so strongly that a complete turn extends less than 2 mm in a direction of a longitudinal axis of the applicator.
 12. The applicator according to claim 1, wherein at least one of the ribs has a base section and a tip section, with the tip section of a the at least one rib protuding beyond the base section of the at least one rib on both sides in a circumferential direction, by an amount which is at least 50% of a smallest circumferential extension of the base section of the at least one rib.
 13. The applicator according to claim 12, wherein the base section, viewed in the circumferential direction, tapers starting from its connection to the solid core in a radially outward direction.
 14. The applicator according to claim 12, wherein the tip section, viewed in a cross-sectional profile perpendicular to a longitudinal axis of the applicator, has a circular profile over more than 220°.
 15. The applicator according to claim 12, wherein a radial extent of said base section is less than or at most equal to a radial extent of said tip section.
 16. The applicator according to claim 1, wherein each groove between two immediately adjacent ribs in a circumferential direction runs in a straight line in a direction of a longitudinal axis of the applicator.
 17. The applicator according to claim 1, wherein at least some of said filaments form bristles, and a free end of each bristle has an end face that is beveled over an entire surface.
 18. The applicator according to claim 17, wherein the free end of said bristles has an end face which is beveled in a gable roofed manner.
 19. The applicator according to claim 17, wherein the free end of said bristles has an end face which is beveled in a pyramidal manner. 